nat: Move the IMSI/TMSI filtering to a new and dedicated file

Move all routines related to filtering to a separate file.

1 files changed, 0 insertions, 281 deletions

diff --git a/openbsc/src/osmo-bsc_nat/bsc_nat_utils.c b/openbsc/src/osmo-bsc_nat/bsc_nat_utils.c
index c1c233bfa..0c56a8cd9 100644
--- a/openbsc/src/osmo-bsc_nat/bsc_nat_utils.c
+++ b/openbsc/src/osmo-bsc_nat/bsc_nat_utils.c
@@ -374,259 +374,6 @@ int bsc_nat_lst_check_allow(struct bsc_nat_acc_lst *lst, const char *mi_string)
 	return 1;
 }
 
-static int lst_check_deny(struct bsc_nat_acc_lst *lst, const char *mi_string)
-{
-	struct bsc_nat_acc_lst_entry *entry;
-
-	llist_for_each_entry(entry, &lst->fltr_list, list) {
-		if (!entry->imsi_deny)
-			continue;
-		if (regexec(&entry->imsi_deny_re, mi_string, 0, NULL, 0) == 0)
-			return 0;
-	}
-
-	return 1;
-}
-
-/* apply white/black list */
-static int auth_imsi(struct bsc_connection *bsc, const char *mi_string)
-{
-	/*
-	 * Now apply blacklist/whitelist of the BSC and the NAT.
-	 * 1.) Allow directly if the IMSI is allowed at the BSC
-	 * 2.) Reject if the IMSI is not allowed at the BSC
-	 * 3.) Reject if the IMSI not allowed at the global level.
-	 * 4.) Allow directly if the IMSI is allowed at the global level
-	 */
-	struct bsc_nat_acc_lst *nat_lst = NULL;
-	struct bsc_nat_acc_lst *bsc_lst = NULL;
-
-	bsc_lst = bsc_nat_acc_lst_find(bsc->nat, bsc->cfg->acc_lst_name);
-	nat_lst = bsc_nat_acc_lst_find(bsc->nat, bsc->nat->acc_lst_name);
-
-
-	if (bsc_lst) {
-		/* 1. BSC allow */
-		if (bsc_nat_lst_check_allow(bsc_lst, mi_string) == 0)
-			return 1;
-
-		/* 2. BSC deny */
-		if (lst_check_deny(bsc_lst, mi_string) == 0) {
-			LOGP(DNAT, LOGL_ERROR,
-			     "Filtering %s by imsi_deny on bsc nr: %d.\n", mi_string, bsc->cfg->nr);
-			rate_ctr_inc(&bsc_lst->stats->ctr[ACC_LIST_BSC_FILTER]);
-			return -2;
-		}
-
-	}
-
-	/* 3. NAT deny */
-	if (nat_lst) {
-		if (lst_check_deny(nat_lst, mi_string) == 0) {
-			LOGP(DNAT, LOGL_ERROR,
-			     "Filtering %s by nat imsi_deny on bsc nr: %d.\n", mi_string, bsc->cfg->nr);
-			rate_ctr_inc(&nat_lst->stats->ctr[ACC_LIST_NAT_FILTER]);
-			return -3;
-		}
-	}
-
-	return 1;
-}
-
-static int _cr_check_loc_upd(struct bsc_connection *bsc,
-			     uint8_t *data, unsigned int length,
-			     char **imsi)
-{
-	uint8_t mi_type;
-	struct gsm48_loc_upd_req *lu;
-	char mi_string[GSM48_MI_SIZE];
-
-	if (length < sizeof(*lu)) {
-		LOGP(DNAT, LOGL_ERROR,
-		     "LU does not fit. Length is %d \n", length);
-		return -1;
-	}
-
-	lu = (struct gsm48_loc_upd_req *) data;
-	mi_type = lu->mi[0] & GSM_MI_TYPE_MASK;
-
-	/*
-	 * We can only deal with the IMSI. This will fail for a phone that
-	 * will send the TMSI of a previous network to us.
-	 */
-	if (mi_type != GSM_MI_TYPE_IMSI)
-		return 0;
-
-	gsm48_mi_to_string(mi_string, sizeof(mi_string), lu->mi, lu->mi_len);
-	*imsi = talloc_strdup(bsc, mi_string);
-	return auth_imsi(bsc, mi_string);
-}
-
-static int _cr_check_cm_serv_req(struct bsc_connection *bsc,
-				 uint8_t *data, unsigned int length,
-				 int *con_type, char **imsi)
-{
-	static const uint32_t classmark_offset =
-				offsetof(struct gsm48_service_request, classmark);
-
-	char mi_string[GSM48_MI_SIZE];
-	uint8_t mi_type;
-	int rc;
-	struct gsm48_service_request *req;
-
-	/* unfortunately in Phase1 the classmark2 length is variable */
-
-	if (length < sizeof(*req)) {
-		LOGP(DNAT, LOGL_ERROR,
-		     "CM Serv Req does not fit. Length is %d\n", length);
-		return -1;
-	}
-
-	req = (struct gsm48_service_request *) data;
-	if (req->cm_service_type == 0x8)
-		*con_type = NAT_CON_TYPE_SSA;
-	rc = gsm48_extract_mi((uint8_t *) &req->classmark,
-			      length - classmark_offset, mi_string, &mi_type);
-	if (rc < 0) {
-		LOGP(DNAT, LOGL_ERROR, "Failed to parse the classmark2/mi. error: %d\n", rc);
-		return -1;
-	}
-
-	/* we have to let the TMSI or such pass */
-	if (mi_type != GSM_MI_TYPE_IMSI)
-		return 0;
-
-	*imsi = talloc_strdup(bsc, mi_string);
-	return auth_imsi(bsc, mi_string);
-}
-
-static int _cr_check_pag_resp(struct bsc_connection *bsc,
-			      uint8_t *data, unsigned int length,
-			      char **imsi)
-{
-	struct gsm48_pag_resp *resp;
-	char mi_string[GSM48_MI_SIZE];
-	uint8_t mi_type;
-
-	if (length < sizeof(*resp)) {
-		LOGP(DNAT, LOGL_ERROR, "PAG RESP does not fit. Length was %d.\n", length);
-		return -1;
-	}
-
-	resp = (struct gsm48_pag_resp *) data;
-	if (gsm48_paging_extract_mi(resp, length, mi_string, &mi_type) < 0) {
-		LOGP(DNAT, LOGL_ERROR, "Failed to extract the MI.\n");
-		return -1;
-	}
-
-	/* we need to let it pass for now */
-	if (mi_type != GSM_MI_TYPE_IMSI)
-		return 0;
-
-	*imsi = talloc_strdup(bsc, mi_string);
-	return auth_imsi(bsc, mi_string);
-}
-
-static int _dt_check_id_resp(struct bsc_connection *bsc,
-			     uint8_t *data, unsigned int length,
-			     struct sccp_connections *con)
-{
-	char mi_string[GSM48_MI_SIZE];
-	uint8_t mi_type;
-	int ret;
-
-	if (length < 2) {
-		LOGP(DNAT, LOGL_ERROR, "mi does not fit.\n");
-		return -1;
-	}
-
-	if (data[0] < length - 1) {
-		LOGP(DNAT, LOGL_ERROR, "mi length too big.\n");
-		return -2;
-	}
-
-	mi_type = data[1] & GSM_MI_TYPE_MASK;
-	gsm48_mi_to_string(mi_string, sizeof(mi_string), &data[1], data[0]);
-
-	if (mi_type != GSM_MI_TYPE_IMSI)
-		return 0;
-
-	ret = auth_imsi(bsc, mi_string);
-	con->imsi_checked = 1;
-	con->imsi = talloc_strdup(con, mi_string);
-	return ret;
-}
-
-/* Filter out CR data... */
-int bsc_nat_filter_sccp_cr(struct bsc_connection *bsc, struct msgb *msg,
-			   struct bsc_nat_parsed *parsed, int *con_type,
-			   char **imsi)
-{
-	struct tlv_parsed tp;
-	struct gsm48_hdr *hdr48;
-	int hdr48_len;
-	int len;
-	uint8_t msg_type, proto;
-
-	*con_type = NAT_CON_TYPE_NONE;
-	*imsi = NULL;
-
-	if (parsed->gsm_type != BSS_MAP_MSG_COMPLETE_LAYER_3) {
-		LOGP(DNAT, LOGL_ERROR,
-		     "Rejecting CR message due wrong GSM Type %d\n", parsed->gsm_type);
-		return -1;
-	}
-
-	/* the parsed has had some basic l3 length check */
-	len = msg->l3h[1];
-	if (msgb_l3len(msg) - 3 < len) {
-		LOGP(DNAT, LOGL_ERROR,
-		     "The CR Data has not enough space...\n");
-		return -1;
-	}
-
-	msg->l4h = &msg->l3h[3];
-	len -= 1;
-
-	tlv_parse(&tp, gsm0808_att_tlvdef(), msg->l4h, len, 0, 0);
-
-	if (!TLVP_PRESENT(&tp, GSM0808_IE_LAYER_3_INFORMATION)) {
-		LOGP(DNAT, LOGL_ERROR, "CR Data does not contain layer3 information.\n");
-		return -1;
-	}
-
-	hdr48_len = TLVP_LEN(&tp, GSM0808_IE_LAYER_3_INFORMATION);
-
-	if (hdr48_len < sizeof(*hdr48)) {
-		LOGP(DNAT, LOGL_ERROR, "GSM48 header does not fit.\n");
-		return -1;
-	}
-
-	hdr48 = (struct gsm48_hdr *) TLVP_VAL(&tp, GSM0808_IE_LAYER_3_INFORMATION);
-
-	proto = hdr48->proto_discr & 0x0f;
-	msg_type = hdr48->msg_type & 0xbf;
-	if (proto == GSM48_PDISC_MM &&
-	    msg_type == GSM48_MT_MM_LOC_UPD_REQUEST) {
-		*con_type = NAT_CON_TYPE_LU;
-		return _cr_check_loc_upd(bsc, &hdr48->data[0], hdr48_len - sizeof(*hdr48), imsi);
-	} else if (proto == GSM48_PDISC_MM &&
-		  msg_type == GSM48_MT_MM_CM_SERV_REQ) {
-		*con_type = NAT_CON_TYPE_CM_SERV_REQ;
-		return _cr_check_cm_serv_req(bsc, &hdr48->data[0],
-					     hdr48_len - sizeof(*hdr48),
-					     con_type, imsi);
-	} else if (proto == GSM48_PDISC_RR &&
-		   msg_type == GSM48_MT_RR_PAG_RESP) {
-		*con_type = NAT_CON_TYPE_PAG_RESP;
-		return _cr_check_pag_resp(bsc, &hdr48->data[0], hdr48_len - sizeof(*hdr48), imsi);
-	} else {
-		/* We only want to filter the above, let other things pass */
-		*con_type = NAT_CON_TYPE_OTHER;
-		return 0;
-	}
-}
-
 struct gsm48_hdr *bsc_unpack_dtap(struct bsc_nat_parsed *parsed,
 				  struct msgb *msg, uint32_t *len)
 {
@@ -648,34 +395,6 @@ struct gsm48_hdr *bsc_unpack_dtap(struct bsc_nat_parsed *parsed,
 	return (struct gsm48_hdr *) msg->l4h;
 }
 
-int bsc_nat_filter_dt(struct bsc_connection *bsc, struct msgb *msg,
-		      struct sccp_connections *con, struct bsc_nat_parsed *parsed)
-{
-	uint32_t len;
-	uint8_t msg_type, proto;
-	struct gsm48_hdr *hdr48;
-
-	if (con->imsi_checked)
-		return 0;
-
-	/* only care about DTAP messages */
-	if (parsed->bssap != BSSAP_MSG_DTAP)
-		return 0;
-
-	hdr48 = bsc_unpack_dtap(parsed, msg, &len);
-	if (!hdr48)
-		return -1;
-
-	proto = hdr48->proto_discr & 0x0f;
-	msg_type = hdr48->msg_type & 0xbf;
-	if (proto == GSM48_PDISC_MM &&
-	    msg_type == GSM48_MT_MM_ID_RESP) {
-		return _dt_check_id_resp(bsc, &hdr48->data[0], len - sizeof(*hdr48), con);
-	} else {
-		return 0;
-	}
-}
-
 static const char *con_types [] = {
 	[NAT_CON_TYPE_NONE] = "n/a",
 	[NAT_CON_TYPE_LU] = "Location Update",